KVM Vulnerability in Linux Kernel Impacting Arm64 Architecture

CVE-2026-64555

What is CVE-2026-64555?

A vulnerability has been identified in the Linux kernel's KVM component that affects the arm64 architecture. Specifically, the issue arises in the kvm_hyp_handle_mops() function, where it incorrectly resets the single-step state machine during MOPS exceptions. This defect hinders the correct restoration of SPSR_EL2 by failing to translate the synthetic state value produced by vcpu_cpsr() before writing back to hardware. This oversight could allow for improper state handling during nested virtualization scenarios. The resolution involves direct modification to SPSR_EL2, thereby avoiding the complications associated with synthetic states and ensuring accurate resynchronization upon subsequent transitions back to KVM.

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